Which bond describes the linkage between glycerol and fatty acids?

• A. peptide bonds
• B. glycosidic bonds
• C. phosphodiester bonds
• D. ester linkages

Answer: (D)

When fats form, fatty acids attach to glycerol through ester bonds. Glycerol has three hydroxyl (–OH) groups and fatty acids have carboxyl (–COOH) groups. During esterification, the –OH of glycerol and the carboxyl group of a fatty acid join, releasing water and creating an ester linkage. In triglycerides, all three sites can form these ester bonds, linking three fatty acids to one glycerol. This type of bond is distinct from peptide bonds (between amino acids), glycosidic bonds (between sugars), and phosphodiester bonds (between nucleotides).